Replace the pour lid supplied with your Mini Classic Distiller with the retrofit lid, and place the post filter into the center hole. Before using a new postfilter cup, submerse the postfilter cup in some hot water for 10 minutes to condition the filter and release any air bubbles, then run some water through it to release any carbon fines. Place the jar under the fitting so that the distilled water will dispense into the postfilter cup. The image to the right shows how a successful retrofit should look.